I believe it’s some kind of plastic, but not a “breakable “ plastic. It’s harder than heck and I don’t think you could break it. It might have some type of nylon in it too, but it’s TOUGH!
I have this chopper and love it, but it is not something that I would expect to work well with oranges.
Apples - yes. Oranges - no.
They are too soft and don't have a core.